Children's Antibodies Point to Less Severe COVID-19 Cases, Study Finds

Young child wearing mask and using hand sanitizer.

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Key Takeaways

  • Children and adults respond differently to SARS-CoV-2, the virus that causes COVID-19, which is evident from antibody profiles, a new study finds.
  • Children are more likely to have a shorter course of the infection and are contagious for a shorter amount of time compared to adults.
  • Researchers believe children's innate immune systems may be one reason behind this difference, but are looking to complete more studies.

Adults and children generate different types and amounts of antibodies in response to COVID-19 compared to adults, a new study shows. The findings mean that most children clear the virus more easily than adults due to their different immune responses and courses of infection.

The study in Nature suggests a “stark contrast” between antibodies of SARS-CoV-2, the virus that causes COVID-19, in kids and adults, study author Donna Farber, PhD, a professor and immunologist at Columbia University, tells Verywell.

The researchers looked at 47 children, 16 of whom were treated at Columbia University Irving Medical Center for multisystem inflammatory syndrome (MIS-C) and 31 of whom were positive for the SARS-CoV-2 after visiting the medical center to receive treatment for other conditions. Both groups of kids showed the same antibody profile, which was different from adults. They also examined 32 adults at the hospital with different levels of COVID-19-severity.

Farber says children primarily produce immunoglobulin G (IgG) antibodies to the spike protein on the virus surface, but not significantly to another key protein called the nucleocapsid (N) protein.

By contrast, adults with severe disease or those who recovered from mild disease produced anti-S antibodies and also had significant anti-N antibodies, she explains.

The distinct antibody profile in children, and specifically, the lack of substantial anti-N antibodies, indicates a reduced infection course in children. N proteins are only released from infected cells—meaning a larger spread of infection leads to a higher anti-N antibodies count, Farber says.

“The fact that there were low anti-N antibody levels in kids suggests that the infection is becoming disseminated in the body, which signifies a shorter infectious course and that children are likely infectious for a much shorter period of time,” Farber says.

What This Means For You

If a child contracts COVID-19, they may experience a less severe form of the infection. But they are still contagious. Make sure your child is following safety precautions like social distancing, washing hands, and wearing masks.

Assessing Antibodies

“Kids may clear this virus more efficiently than adults and they may not need a strong antibody immune response to get rid of it,” Matteo Porotto, PhD, one of the study authors and associate professor of viral molecular pathogenesis in the Columbia University Department of Pediatrics, said in a statement.

Farber says the neutralizing activity of the anti-S antibodies—a feature of immune protection—is lower overall in children compared to adults. Adults, even those in their 20s, showed neutralizing antibodies. And those who were hit hardest by the virus had the most neutralizing activity.

Farber believes this is due to the fact that the virus lingered inside their bodies for a longer period of time.

“There is a connection between the magnitude of your immune response and the magnitude of the infection: The more severe the infection, the more robust the immune response, because you need to have more immune cells and immune reactions to clear a higher dose of a pathogen,” she said in the statement.

Compared to adults, kids produced very few antibodies against a viral protein only visible to the immune system after cells are infected. This suggests that the infection doesn’t widely spread or kill many of their cells, Farber explained.

“Because children clear the natural virus rapidly, they do not have a widespread infection and they do not need a strong antibody response,” Porotto added in the statement. 

As children generally have a lower course of infection, they may be infectious for a shorter period of time compared to adults. They may be therefore less likely to spread the virus. The researchers note that they did not measure the viral load in children studied.

“People should understand that the immune response in children is very different from that in adults, and that a less robust immune response can indicate an effective and efficient clearance of a pathogen,” Farber says. “Our results that the most severely ill patients had the highest antibody responses are consistent with what others have found. In the case of children, who don’t get very ill, their immune response magnitude is lower, indicating that they have likely efficiently cleared the virus before it could disseminate in the body and do a lot of damage."

Adults and Kids Handle COVID-19 Differently

The medical community already knows that most children handle the virus well, while adults with COVID-19 tend to struggle more.

“Children are uniquely adapted to see pathogens for the first time. That's what their immune system is designed to do," Farber said in the statement. "Children have a lot of naive T cells that are able to recognize all sorts of new pathogens, whereas older people depend more on our immunological memories. We're not as able to respond to a new pathogen like children can."

Burak Bahar, MD, a pathologist at Children’s National in Washington, D.C. who was not affiliated with the research, tells Verywell the study shows there’s an age-related change in terms of the body’s immune response to the virus.

“The amount of the antibody produced and the target site of the antibody do show changes with age,” Bahar says. “Each age group has different kinetics of fighting infections. The more we learn about this disease [COVID-19] and about our bodies’ responses, then we could be able to use this information to treat and prevent infections using different methods for age groups.”

Children’s Vaccine Response

The researchers say their research indicates children won’t have a weaker response to a vaccine.

Even though children don’t produce neutralizing antibodies in response to natural infection with SARS-CoV-2, vaccines are designed to generate a protective immune response in the absence of an infection, Farber said in the statement. 

“Children respond very well to vaccines, and I think they will develop good neutralizing antibody responses to a SARS-CoV-2 vaccine, and they'll probably be better protected than the adults,” she said.

Farber noted that some vaccine trials are currently enrolling children. The medical community will need data on children to understand how children respond to that vaccine and how it works in their bodies.

“Because the vaccines that are currently in trials do not involve an infection, our results measuring the antibody response to the infectious virus would not predict a children’s response to a vaccine,” she says. But because they generally respond well to vaccines and generate antibody responses, she anticipates that will be the case for a COVID-19 vaccine.

Understanding Children's Immune Response

The team still doesn’t know how children are able to clear the virus more easily than adults. They aren’t sure what’s missing in the adult immune system that makes it more difficult to overcome the virus.

They’re hoping to evaluate differences in T-cell response, which are a type of white blood cell of key importance to the immune system. They want to look specifically at T cells in our lungs. Farber’s previous research found that T cells in the lungs are more vital in fighting lung infections than T cells traveling through the body in our blood.

Children who have SARS-CoV-2 may produce a stronger response to the virus based on their innate immune system. Previous research indicates that adults with SARS-CoV-2 may have a delayed innate immune response, the researchers note in their statement.

“If the innate response is really strong, that can reduce the viral load in the lungs, and the antibodies and T cells of the adaptive response have less to clear up,” Farber said in the statement. 

It’s also possible that children’s cells express fewer proteins that the virus needs to infect human cells, they noted. They’ll be looking at those possibilities by testing children’s cells.

“There are still all these issues that we have very little information about,” Porotto said in the statement. “The interaction between the virus and the host is the reason why we see so much diversity in responses to this virus, but we don't understand enough about this virus yet to really determine what leads to severe disease and what leads to mild disease."

The antibody profile isn’t the only potential indicator of what causes some children to have severe cases of COVID-19 that include the multi-inflammatory syndrome (MIS-C).

There are many internal and external variables that could cause a child to have a serious disease or a non-symptomatic presentation. Studies are still ongoing to identify these variables, Bahar says, adding that she would still like to know whether the antibodies can prevent re-infection in pediatric and adult patients.

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  1. Weisberg, S.P., et al. Distinct antibody responses to SARS-CoV-2 in children and adults across the COVID-19 clinical spectrumNature Immunology. Nov. 5, 2020. doi:10.1038/s41590-020-00826-9

  2. Columbia University Irving Medical Center. Children produce different antibodies in response to new coronavirus. Updated November 5, 2020.